Gonadotrophins, not testosterone, influence musculoskeletal pain in men
MedWire News: Men with elevated levels of gonadotrophins appear to be more likely to experience musculoskeletal pain and develop more severe chronic widespread pain (CWP) than their peers with lower levels, study results show.
However, contrary to expectations, sex hormones including testosterone had no discernable effect on pain levels, leading study co-author Abdelouahid Tajar (University of Manchester, UK) and colleagues to call for studies to elucidate the underlying mechanisms.
Fibromyalgia is a non-inflammatory rheumatic disorder characterized by CWP and is one of the most common reasons for consultation at rheumatology clinics in Western Europe and North America.
The condition is more prevalent among women and studies have shown that fibromyalgia most often develops during the menopausal transition. Such observations have led to suggestions that declines in female sex hormones, mainly estrogens, may be linked to the occurrence of pain among women.
Similarities have also been drawn in men in terms of testosterone having a putative protective role against the development of musculoskeletal pain.
To investigate, the researchers recruited 3206 men aged 40 to 79 years from= eight European centres participating in the European Male Aging Study (EMAS).
Fasting blood samples were analyzed for testosterone, estradiol, luteinising hormone (LH), and follicle-stimulating hormone (FSH), and patients also completed a lifestyle questionnaire, detailing the occurrence of musculoskeletal pain over the past month.
In all, 41% of men reported no pain in the past month, 9% reported pain that met the American College of Rheumatology (ACR) criteria for CWP, and 50% were classified as having other musculoskeletal pain.
While testosterone and estradiol showed no association with musculoskeletal pain, LH and FSH levels were positively correlated with pain, after adjustment for age and other possible confounders.
Compared with those in the lowest tertile of LH, those in the highest tertile were more likely to report some musculoskeletal pain (relative risk ratio[RRR]=1.28) and also CWP (RRR=1.51). Similar trends were reported for FSH with corresponding RRRs of 1.23 and 1.47, respectively.
Tajar et al note that the LH receptor has been localized not only in the reproductive organs but also as a functional protein within the central nervous system, including regions of the brain involved in sensory functions.
"It is biologically plausible, therefore, that LH may have either direct effects within the central nervous system or indirect effects via regulation of neurosteroid production," they conclude in the journal Pain.
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By Andrew Czyzewski